class Watcher {
	constructor() {
		this.deps = {}
	}
	push({dataKey, domKey}) {
		this.deps[dataKey] = this.deps[dataKey] || []
		this.deps[dataKey].push(domKey)
	}
	update(dataKey, cb) {
		if(this.deps[dataKey]) {
			cb(this.deps[dataKey])
		}
	}
}